1. Field of the Invention
The present invention generally relates to a method for fabricating an active driven display, and more particularly, to a method for fabricating an active organic electroluminescence display and a thin film transistor array substrate.
2. Description of Related Art
As the high technology continues to evolve, digitalized image devices have become popular products in every day life. Among these digitalized image devices, the most appealing products are liquid crystal displays (LCDs) implementing thin film transistors as driven elements and organic electroluminescence displays (OELDs), wherein these thin film transistors are formed on a thin film transistor array substrate.
FIGS. 1A-1E are cross-sectional views of the processing flow for fabricating a conventional thin film transistor array substrate. Referring to FIG. 1A, a plurality of thin film transistors 110, as well as scan lines (not shown) and data lines (not shown) electrically connected thereto are formed on a substrate 100. Then, a protection layer 102 is formed on the substrate 100 to cover the thin film transistors 110, as well as the scan lines and data lines. Subsequently, referring to FIG. 1B, a plurality of contact holes 104 are formed in the protection layer 102 by using photolithography and etching processes, and then expose a drain-metal layer 112 of the thin film transistors 110. Afterwards, referring to FIG. 1C, a transparent conductor layer 106 is formed on the protection layer 102, which in turn fills in the contact holes so as to be electrically connected to the drain-metal layer 112. Referring to FIG. 1D, a positive type photoresist layer 108 is formed on the transparent conductor layer 106, which is then subjected to the photolithography and etching processes with a mask 120 so as to pattern the transparent conductor layer 106. Referring to FIG. 1E, a plurality of pixel electrodes 130 is formed on the substrate 100 after the positive type photoresist layer 108 is removed.
To a general LCD, the thin film transistor substrate is mostly accomplished when a structure as shown in FIG. 1E is obtained. One of ordinary skill in the art should realize that the aforementioned processing flow for fabricating the thin film transistor substrate at least needs 5 masks. However, in addition to the preceding 5 masks, the processing flow for fabricating an active organic electroluminescence display further requires an extra mask for forming a pixel define layer (PDL) 140, as shown in FIG. 1F, so as to define dispositions for a subsequently deposited organic electroluminescence layer 150. In other words, the processing flow for fabricating the active organic electroluminescence display at least needs 6 masks, which makes this processing flow complicated and accordingly increases fabricating cost.